This invention relates to new solventless cleaning and treating compositions for carpet. This invention also relates to a method for cleaning and treating carpet with these compositions to impart anti-soiling and stain release properties to the carpet.
For many decades, carpet has been the floor covering of choice for improving both the aesthetics and comfort in residential homes and commercial buildings. Though very pleasing in appearance and convenience when new, the carpet over time inevitably is susceptible to staining by foods and beverages and also discoloration due to soil pick-up a caused by foot traffic.
To minimize the effect of these assaults, various treatments have been applied to carpet either at the carpet mill or directly after installation (henceforth referred to as xe2x80x9cearly applied treatmentsxe2x80x9d). Such early applied treatments include (a) fluoroaliphatic compounds and silsesquioxane polymers to provide soil resistance, (b) stainblockers to prevent adherence to, and to facilitate release of, stains from fibers, and (c) various combinations thereof. However, though these early applied treatments may impart good initial protection to carpet, the ability of the treated carpet fibers to resist both soiling and staining gradually diminishes over time due to foot abrasion and soil and stain buildup. At this point, the carpet must be cleaned to restore its initial appearance. Unfortunately, during cycles of carpet cleaning and use, early applied treatments can become ineffective through contamination or may be removed from the carpet, leaving the carpet susceptible to accelerated discoloration from staining and soiling.
In order to maintain satisfactory stain and soil resistance of the carpet after cleaning (i.e., to bolster the resistance of the cleaned carpet to that of the early applied treated carpet), soil and stain resistant agents are normally applied to the cleaned carpet in a separate application step. This post-application is necessitated because of the incompatibility of the anti-soiling chemicals with the cleaning detergent systems and resulting ineffectiveness of such mixtures. For example, anti-soiling chemicals such as perfluoroalkyl group-containing polymers tend to separate out from surfactants thus limiting shelf-life. Additionally, the effectiveness of anti-soiling chemicals and surfactants is related to pH. Anti-soiling chemicals are more effective in an acidic environment while surfactants are more effective in a basic environment thus making it difficult to produce a single composition containing both components while maintaining the desired properties.
Thus, it would be desirable to employ a one-stop cleaning/treating process. But in order to effectively employ such a one-step process, anti-soiling and stainblocking agents must be compatible with cleaning detergents. Additionally, such agents must be quickly exhausted onto the carpet fibers under vacuuming condition, since the time window between contacting the carpet with the cleaning detergents and treating agents and removing such detergents and agents is extremely short. Vacuum application tends to extract the treating agents along with the dirty detergent-containing waste water, resulting in insufficient long-term carpet protection.
Despite these attempts, there continues to be a need an organic solvent-free carpet cleaning system that can simultaneously effectively clean carpet and provide long term anti-soiling and stainblocking protection to the cleaned carpet.
In one aspect, this invention relates to an aqueous composition having a pH of at least 6 that includes a stainblocking polymer, silsesquioxane anti-soiling polymer, surfactant, and optional sequestering agent, or salt.
In another aspect, this invention relates to a method for cleaning a fibrous polyamide substrate and imparting superior soil and stain resistance properties to the cleaned carpet that includes (a) water extracting the substrate with an aqueous composition of this invention, and (b) vacuum removal of the composition from the cleaned and treated substrate.
A further aspect of the invention relates to a method for cleaning a fibrous polyamide substrate and imparting superior soil and stain resistance properties to the cleaned carpet that includes (a) water extracting the substrate with an aqueous composition of this invention, (b) vacuum removal of the composition from the cleaned and treated substrate; and contacting the substrate with an aqueous composition comprising a stainblocker and a silsesquioxane.
The carpet cleaning and treating compositions of this invention may be used to effectively clean and treat soiled and stained carpet using a one step process, imparting superior anti-soiling and stainblocking properties to the cleaned carpet. This process can be employed with previously installed carpet or, alternatively, can be used in the carpet factory to clean and treat uninstalled, previously untreated carpet. The one step process described in this invention avoids the additional time and labor costs necessitated in a two-step cleaning and treating process as well as reduces the total amount of aqueous cleaner and treatment applied. This reduction in aqueous cleaner amount leads to two advantages: (1) it minimizes damage of the carpet due to water penetration and potential dimensional instability, and (2) it reduces the energy costs in the ovens required to dry the water. Although it is economically more desirable to clean and treat in one step, the carpet cleaning and treating compositions of this invention can be applied onto installed carpets before or after the carpet is cleaned. Additionally, the carpet cleaning and treating compositions of this invention can be applied onto installed carpets cleaned with compositions other than those disclosed in this application. Furthermore, the carpet cleaning and treating compositions of this invention can be applied onto installed carpets that have not been previously imparted with anti-soiling and/or stain release properties.
Cleaning and treating carpet compositions of this invention can be utilized by carpet distributors and professional cleaners as well as by xe2x80x9cdo-it-yourselfxe2x80x9d consumers. The cleaning and treating compositions of this invention are shelf stable and can be stored at high concentration without separation.
This invention relates to new solventless cleaning and treating compositions for carpet. This invention also relates to a method for cleaning and treating carpet with these compositions to impart anti-soiling and stain release properties to the carpet. In particular, the present invention is directed to aqueous compositions having a pH of at least 6 that include a stainblocking polymer, silsesquioxane anti-soiling polymer, surfactant, and optional sequestering agent, or salt. While the present invention is not so limited, an appreciation of various aspects of the invention will be gained through a discussion of the examples provided below.
The recitation of numerical ranges by endpoints includes all numbers and fractions subsumed within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).
All numbers and fractions thereof are presumed to be modified by the term xe2x80x9cabout.xe2x80x9d
As used herein, xe2x80x9caxe2x80x9d includes both the singular and plural.
The general definitions used herein have the following meanings within the scope of the present invention.
The term xe2x80x9calkylxe2x80x9d refers to, unless stated otherwise, straight or branched hydrocarbon radicals, such as methyl, ethyl, propyl, butyl, octyl, isopropyl, tert-butyl, sec-pentyl, and the like. Alkyl groups can either be unsubstituted or substituted with one or more substituents, e.g., halogen, alkoxy, aryl, arylalkyl, aralkoxy and the like. Alkyl groups include, for example, 1 to 25 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms.
The term xe2x80x9chaloxe2x80x9d refers to, unless stated otherwise, fluoride, chloride, bromide, and iodide radicals.
The term xe2x80x9carylxe2x80x9d refers to, unless stated otherwise, monovalent unsaturated aromatic carbocyclic radicals having a single ring, such as phenyl, or multiple condensed rings, such as naphthyl or anthryl, which can be optionally substituted by substituents such as halogen, alkyl, arylalkyl, alkoxy, aralkoxy, and the like.
The term xe2x80x9calkoxyxe2x80x9d refers to, unless stated otherwise, xe2x80x94O-alkyl with alkyl as defined above. Alkoxy groups include, for example, methoxy, ethoxy, propoxy, isopropoxy, and the like.
The term xe2x80x9calkarylxe2x80x9d refers to, unless stated otherwise, an alkyl radical defined as above bonded to an aryl radical as defined above (e.g. alkyl-aryl-).
A wide variety of stainblocking polymers may be used in the compositions of this invention. Included among the useful stainblocking polymers are sulfonated aromatic polymers, polymers that are derived from at least one or more xcex1- and/or xcex2-substituted acrylic acid monomers, and hydrolyzed copolymers of at least one or more ethylenically unsaturated monomers and maleic anhydride. Also useful as stainblocking polymers are blends of at least two or more of these polymers, reaction products of at least two or more of the monomers from which these polymers may be derived, reaction products of at least one or more of the monomers from which the polymers may be derived and at least one or more of the polymers, and materials obtained by polymerizing at least one or more of the monomers in the presence of one or more of the polymers.
Sulfonated aromatic polymers are a preferred class of stainblocking polymers. Desirable examples may comprise a condensation polymer of an aldehyde (e.g., formaldehyde or acetaldehyde) and a sulfonated aromatic compound, or a subsequently sulfonated condensation polymer of an aldehyde and an aromatic compound. Various sulfonated aromatic compounds are available for use in the stainblocking compositions of the invention. However, among the most preferred materials are those which include hydroxyl functionality such as bis(hydroxy phenyl sulfone), hydroxy benzenesulfonic acid, hydroxynaphthalenesulfonic acid, sulfonated 4,4xe2x80x2-dihydroxydiphenylsulfone, and blends thereof. Other useful sulfonated aromatic polymers comprise a copolymer of an ethylenically unsaturated aromatic monomer (e.g., styrene) and a sulfonated ethylenically unsaturated aromatic monomer (e.g., styrene sulfonate).
Another preferred class of stainblocking polymers are polymers derived from at least one or more xcex1- and/or xcex2-substituted acrylic acid monomers. These monomers have the general structure HR1Cxe2x95x90C(R)COOX, wherein R and R1 are independently selected from hydrogen, organic radicals and halogens, and X is independently selected from hydrogen, organic radicals and cations. Particularly preferred examples of the resulting polymers are acrylic polymers; i.e., polyacrylic acid, copolymers of acrylic acid and one or more other monomers that are copolymerizable with acrylic acid, and blends of polyacrylic acid and one or more acrylic acid copolymers. Even more preferred, however, are methacrylic polymers which includes polymethacrylic acid, copolymers of methacrylic acid and one or more other monomers that are copolymerizable with methacrylic acid, and blends of polymethacrylic acid and one or more methacrylic acid copolymers.
A third preferred class of stainblocking polymers includes hydrolyzed copolymers of at least one or more ethylenically unsaturated monomers and maleic anhydride. The ethylenically unsaturated monomers can be alpha-olefin type monomers (e.g. 1-alkenes), alkyl vinyl ethers or, more preferably, aromatic monomers such as styrene.
Quite useful stainblocking polymers may be obtained by blending together two or more polymers selected from among the different general classes of polymers described above, reacting together at least two or more monomers from which the different general classes of polymers are derived, reaction products of at least one or more of the monomers from which the polymers may be derived and at least one or more of the polymers, or by polymerizing at least one or more of the monomers in the presence of one or more of the polymers.
For example, one or more xcex1- and/or xcex2-substituted acrylic acid monomers may be polymerized together and, subsequent to the polymerization, blended with a sulfonated aromatic polymer. Alternatively, the xcex1- and/or xcex2-substituted acrylic acid monomers can be polymerized in the presence of a sulfonated aromatic polymer.
In another example, a hydrolyzed copolymer of ethylenically unsaturated monomer and maleic anhydride may be combined with a sulfonated aromatic polymer, and, optionally, a polymer derived from at least one or more xcex1- and/or xcex2-substituted acrylic acid monomers.
By xe2x80x9cmonomerxe2x80x9d is meant a polymerizable single unit (typically of low molecular weight) that provides repeating units in the ultimate polymer, as well as partially reacted materials that can still participate in a polymerization reaction so as to provide repeating units in the ultimate polymer. The expression xe2x80x9cat leastxe2x80x9d recognizes, as explained below, that monomers in addition to those mentioned may participate in the polymerization.
Sulfonated aromatic polymers useful in the invention may be obtained by condensation polymerizing an aldehyde with a sulfonated aromatic compound, the resulting polymer sometimes being referred to herein as either a sulfonated aromatic condensation polymer or as a condensation polymer. The resulting condensation polymer should contain a significant number of sulfonate groups. It is also preferred that the resulting condensation polymer be substantially soluble in water to simplify handling and application of the stainblocking composition to a substrate at normal temperatures (room temperature to 100xc2x0 C., where xe2x80x9croom temperaturexe2x80x9d refers to a temperature of 20 to 25xc2x0 C.).
Any aldehyde that can be condensation polymerized with a sulfonated aromatic compound may be used in the invention. Suitable examples of such aldehydes include acetaldehyde, benzaldehyde, furfuraldehyde, and, most preferably, formaldehyde. Suitable sulfonated aromatic compounds for forming the condensation polymer include monomers such as benzene sulfonic acid (which, in general, may contain various combinations of alkyl, hydroxy and alkoxy substituents), toluene sulfonic acid, xylene sulfonic acid (e.g., 2,4-dimethyl benzene sulfonic acid), phenyl 4-sulfonic acid, cumene sulfonic acid, dodecylbenzene sulfonic acid, sulfonated diphenyl ether, benzaldehyde sulfonic acid, aminobenzene sulfonic acid, alkoxybenzenesulfonic acid, benzophenone sulfonic acid, sulfonated derivatives of styrene, dodecyl diphenyloxide disulfonic acid, sulfonated derivatives of naphthalene (e.g., naphthalene sulfonic acid), which derivatives may generally contain various combinations of alkyl, hydroxy and alkoxy substituents such as, alkylnaphthalene sulfonic acid (e.g., methylnaphthalene sulfonic acid) and alkoxynaphthalene sulfonic acid.
Including hydroxyl functionality in the sulfonated aromatic compound may enhance its solubility in water. Hydroxyl functionality may be introduced into the sulfonated aromatic compound (so as to form a sulfonated hydroxyaromatic compound) by either sulfonating a phenolic compound, or by polymerizing the aldehyde and the sulfonated aromatic compound with a hydroxyaromatic material (preferably a phenolic compound). Phenolic compounds useful in either approach include phenol, halogenated phenol (e.g., chlorophenol or trifluoromethylphenol), naphthol, dihydroxydiphenylsulfide, resorcinol, catechol, hydroxyarylcarboxylic acid (e.g., salicylic acid), hydroxyphenylphenyl ether, phenylphenol, alkylphenol (e.g., nonylphenol or cresol), dihydroxydiphenylsulfone, and bis(hydroxyphenyl)alkane (e.g., 2,2-bis(hydroxyphenyl)propane or 2,2,-bis(hydroxyphenyl)hexafluoropropane). Resulting materials include sulfoalkylated phenol, (e.g., sulfomethylated dihydroxydiphenyl sulfone). Particularly preferred sulfonated hydroxyaromatic compounds include bis(hydroxyphenyl)sulfone, hydroxybenzenesulfonic acid, hydroxynapthalenesulfonic acid, and sulfonated 4,4xe2x80x2-dihydroxydiphenylsulfone.
Enhanced solubility in water may also be obtained by providing the sulfonated aromatic compound as a salt based on, for example, sodium, potassium, or ammonium, such as sodium xylene sulfonate, ammonium xylene sulfonate, sodium toluene sulfonate, sodium cumene sulfonate, ammonium cumene sulfonate, potassium toluene sulfonate, potassium cumene sulfonate, and potassium xylene sulfonate.
Particularly preferred condensation polymers consist essentially of repeating units of the formula 
where R is the same or different in each unit, and is either hydrogen or a radical selected from the group consisting of xe2x80x94SO3X, 
where X is hydrogen or a cation such as sodium or potassium, provided that the resulting polymer contains a sufficient number of sulfonate groups (typically at least 30%). Even more preferred are condensation polymers having these structures and which are water soluble, have at least 40% of the repeating units containing an xe2x80x94SO3X radial, and have at least 40% of the repeating units containing the group xe2x80x94SO2xe2x80x94.
Sulfonated aromatic condensation polymers useful in the invention are described in U.S. Pat. No. 4,680,212 (Blyth et al.), U.S. Pat. No. 4,875,901 (Payet et al.), U.S. Pat. No. 4,940,757 (Moss, III et al.), U.S. Pat. No. 5,061,763 (Moss, III et al.), U.S. Pat. No. 5,074,883 (Wang), and U.S. Pat. No. 5,098,774 (Chang).
Sulfonated aromatic condensation polymers useful in the invention can be prepared by methods known to those skilled in the art. Sulfonation of phenolic compounds is described in, for example, Sulfonated and Related Reactions, E. E. Gilbert, Interscience Publishers, 1965. Methods of preparing condensation polymers of sulfonated aromatic compounds with formaldehyde are described in U.S. Pat. No. 1,901,536 (Schafer), U.S. Pat. No. 1,972,754 (Biedernann), U.S. Pat. No. 1,988,985 (Schafer), U.S. Pat. No. 2,112,361 (Fischer), U.S. Pat. No. 2,171,806 (Russell, et al.), U.S. Pat. No. 4,680,212 (Blyth et al.), U.S. Pat. No. 4,940,757 (Moss, III et al.), U.S. Pat. No. 5,061,763 (Moss, III et al.), and Phenolic Resins, A. Knopf et al., Springer-Verlag, 1985.
In general, an aromatic compound such as phenol, naphthalene or naphthol is sulfonated, for example by reacting it with a sulfonating compound such as sulfuric acid, chlorosulfonic acid or alkaline sulfite so as to form a sulfonated aromatic compound. The sulfonated aromatic compound is then condensation polymerized with formaldehyde or other aldehyde, typically under acidic conditions. Mixtures of different sulfonated aromatic compounds can also be polymerized. Typically, one mole of sulfonated aromatic compound is reacted with 0.5 to 1.2 mole of aldehyde. The sulfonated aromatic condensation polymer can be subsequently reacted with a base (e.g., sodium hydroxide, potassium hydroxide, or ammonium hydroxide) so as to form a sulfonic acid salt. Currently marketed condensation polymers are typically sold as a sodium sulfonate salt.
Alternatively, a sulfonated aromatic condensation polymer may be prepared by reacting an unsulfonated hydroxy aromatic compound (e.g., a phenolic compound such as phenol, naphthol, etc.) with an aldehyde such as formaldehyde and then sulfonating the resulting condensation polymer by treatment with fuming sulfuric acid.
Examples of useful, commercially available sulfonated aromatic condensation polymers include Erional(trademark) NW (Ciba-Geigy Limited; containing a naphthalene sulfonic acid polymer with formaldehyde and 4,4xe2x80x2-dihydroxydiphenylsulfone), Erional(trademark) PA (polymer of phenol sulfonic acid, formaldehyde, and 4,4xe2x80x2 dihydroxydiphenyl sulfone from Ciba-Geigy), 3M(trademark) brand stain release concentrate FX-369(trademark) (3M Co.), Tamol(trademark) SN (Rohm and Haas Co.), Mesitol(trademark) NBS, Bayprotect CL or CSD(trademark) (Bayer AG), Nylofixan(trademark) P (containing a formaldehyde condensation copolymer of 4,4xe2x80x2-dihydroxydiphenylsulfone and 2,4-dimethylbenzenesulfonic acid, manufactured by Sandoz Corp.), and Intratex(trademark) N (Crompton and Knowles Corp.). The sulfonated aromatic polymers are typically purchased commercially as a 30 to 40% solids aqueous solution that can contain other compounds, including aromatic sulfonic acids and glycols.
The effectiveness of a sulfonated aromatic condensation polymer in imparting stain resistance to a substrate may be improved by providing the condensation polymer in the form of a divalent metal salt. These salts are water soluble and are substantially free of sulfonic acid moieties (i.e., xe2x80x94SO3H groups); that is, they typically contain less than 1 mole percent sulfonic acid moieties. The salt form of the polymer may be obtained by reacting the condensation polymer with a divalent metal oxide or hydroxide, or the divalent metal salt of a weak acid (e.g., carbonic acid, boric acid, or a carboxylic acid) so as to form an aqueous solution having a pH of at least 3. In another approach, a sulfonated aromatic compound that is used to prepare the condensation polymer may first be converted to a salt (by using a divalent metal oxide or hydroxide, or a divalent metal salt of a weak acid) before reaction with an aldehyde to yield the salt form of the polymer. Suitable divalent metal oxides or hydroxides include oxides and hydroxides of calcium, magnesium and zinc. Divalent metal salts of weak acids include carbonates, bicarbonates, acetates, formates and borates of calcium, magnesium and zinc. Even further improvements in stain resistance may be achieved by adding small amounts (less than 0.1% SOF, more preferably less than 0.05% SOF) of a divalent metal salt (such as those discussed in the additives section below) to the salt form of the polymer. (% SOF refers to the % solids based on the weight of the fibrous substrate.) Such techniques are described in U.S. Pat. No. 5,098,774 (Chang).
Sulfonated aromatic condensation polymers may discolor with time and assume a yellow tint that can be undesirable, especially depending on the color of the substrate to which the stainblocking composition is applied. Thus, a blue substrate may acquire a greenish cast. One technique for reducing the tendency to change color is to remove color formers inherent in the stainblocking polymer. This can be accomplished by dissolving the condensation polymer in aqueous base so as to form a solution having a pH of 8-12, acidifying the aqueous solution to a pH of a 2 to 7.5, heating the acidified material to a temperature of 50 to 65xc2x0 C. so as to cause phase separation, removing materials which remain water-soluble after acidification and heating (e.g., by filtering, centrifuging or decanting), and dissolving the resultant water-insoluble material in aqueous base to a final pH of at least 8, using heat as necessary to effect dissolution. Strong bases (e.g., sodium hydroxide, potassium hydroxide, lithium hydroxide) may be used. Virtually any acid is suitable, e.g. glacial acetic acid, dilute acetic acid, hydrochloric acid, sulfuric acid, oxalic acid, citric acid, or sulfamic acid. Such techniques are described in U.S. Pat. No. 4,833,009 (Marshall).
Another technique for reducing the tendency to change color is to acylate or etherify a portion of the free hydroxyl groups in the condensation polymer. However, acylating or etherifying the free hydroxyl groups can reduce the stainblocking characteristics of the condensation polymer. Thus, the portion of the free hydroxyl groups that are so treated should strike a balance between a reduced tendency to yellow and effective stainblocking. Useful acylating agents include acetic anhydride and ethylchlorofomate (conversion of 50% to 80% of the phenolic hydroxyl groups). Chloroacetic acid is a useful etherifying agent (conversion of 40% to 60% of the phenolic hydroxyl groups). The acylated and etherified products can be prepared by dissolving the condensation polymer in an aqueous medium having a pH of 7 or above, preferably 10 or 11 to 13 or 14 (the actual pH depending on the acylating or etherifying agent), and at a temperature that favors acylation or etherification. The water-insoluble phase can be separated from the unwanted water solution by filtering, centrifuging, decanting, etc., and then redissolved in a hydroxyl-functional material, such as ethylene glycol, 1,3-propylene glycol, or 1,3-butylene glycol. Such techniques are described in U.S. Pat. No. 4,963,409 (Liss et al.).
In another embodiment, sulfonated aromatic polymers useful in the invention as stainblocking polymers may comprise a copolymer of: (a) one or more ethylenically unsaturated aromatic monomers; and (b) one or more sulfonated ethylenically unsaturated aromatic monomers. Specific examples of ethylenically unsaturated aromatic monomers (a) include styrene, a-methylstyrene, 4-methyl styrene, stilbene, 4-acetoxystilbene, eugenol, isoeugenol, 4-allylphenol, safrole, and mixtures of these materials. Preferably, the sulfonated monomers are water soluble, which can be facilitated by providing the monomer in the form of a salt, for example, salts of alkali metals (e.g., sodium) and ammonium salts. A variety of sulfonated monomers (b) may be used including those which result from sulfonating the ortho and/or para positions of the monomers used to provide ethylenically unsaturated aromatic monomer (a). Particular examples include sodium p-styrene sulfonate, sodium vinyl p-toluene sulfonate, ammonium p-styrene sulfonate.
In the sulfonated aromatic copolymers of this embodiment, the ratio of units derived from monomer (a) to the units derived from monomer (b) is preferably 0.1 to 10:1, more preferably 0.9:1. Materials of this type are described in International Patent Publication No. WO 92/07131 (E. I. du Pont de Nemours and Company). The sulfonated aromatic copolymers can be conveniently prepared by a variety of free radical-initiated polymerization reactions using, for example benzoyl peroxide or 2,2xe2x80x2-azobis (2-methylbutyronitrile).
A second class of stainblocking polymers useful in the invention are polymers of at least one or more (xcex1- and/or xcex2-substituted) acrylic acid monomers, these materials sometimes being referred to herein as (xcex1- and/or xcex2-substituted) acrylic acid polymers. The use of the parenthetical expression xe2x80x9calpha-and/or beta-substitutedxe2x80x9d indicates that substitution of the xcex1- and xcex2-positions of the acrylic acid monomer is independently optional. That is, both positions may be substituted, neither position may be substituted, or either one of the two positions may be substituted without the other-position being substituted. Thus, (xcex1- and/or xcex2-substituted) acrylic acid monomers that are useful in preparing the polymers have the general structure HR1Cxe2x95x90C(R)COOX, wherein R and R1 are independently selected (i.e., they may be the same or they may be different) from hydrogen, organic radicals or halogen, and X is hydrogen, an organic radical, or a cation. Organic radicals that may be used to provide R and R1 include aliphatic hydrocarbons (more preferably, alkyl moieties having 1 to 20, most preferably 1 to 4 carbon atoms such as methyl, ethyl, propyl and butyl), which, optionally, may be sulfonated or halogenated (for example, by chlorine or fluorine); and aromatic hydrocarbons (more preferably, a phenyl group), which, optionally, may be sulfonated, halogenated (for example, by chlorine or fluorine), hydroxylated (e.g., phenol or naphthol), or combinations thereof (e.g., sulfonated phenol or sulfonated naphthol). Halogens that may be used for R and R1 include chlorine and fluorine.
Organic radicals that may be used to provide the X group include both aliphatic moieties (which may be linear, branched or cyclic, and preferably containing 1 to 10 carbon atoms), or aromatic moieties, any of which may, optionally, be halogenated, sulfonated, carboxylated, hydroxylated or ethoxylated, including cationic (e.g., sodium, potassium, ammonium, and quaternary amine) salts of these materials. Cations that may be used to provide X include sodium, potassium, ammonium, and quaternary amine.
Preferred monomers are defined by structures in which R1 is hydrogen, R is an alkyl group having 1 to 4 carbon atoms, phenyl, phenol, sulfonated phenol, naphthol, chlorine, or fluorine, and X is hydrogen, an alkyl group of 1 to 10 carbon atoms, sodium, potassium or ammonium. The most preferred monomer is methacrylic acid (R1 and X are hydrogen, R is methyl).
The (xcex1- and/or xcex2-substituted) acrylic acid polymers are preferably sufficiently water-soluble or water dispersible that uniform application and penetration of the polymer into the substrate surface can be achieved at normal application temperatures (room temperature to 100xc2x0 C.). However, excessive water solubility may reduce the treated substrate""s resistance to staining by acid colorants, as well as the effectiveness of the stainblocking compositions after cleaning the substrate.
The glass transition temperature of the (xcex1- and/or xcex2-substituted) acrylic acid polymers can be as low as 35xc2x0 C. although higher glass transition temperatures are preferred. When polymers having high glass transition temperatures (e.g., 90xc2x0 C. or higher) are used, an additional benefit of improved soil resistance may be obtained.
The weight average molecular weight and the number average molecular weight of the (xcex1- and/or xcex2-substituted) acrylic acid polymers should be selected so as to provide satisfactory stain resistance, water solubility, viscosity, and ability to be handled in conventional stainblocking polymer manufacturing and application processes. Preferably, the lower 90 weight percent of the polymer has a weight average molecular weight of 3,000 to 250,000, and a number average molecular weight of 500 to 50,000, more preferably 800 to 10,000. Generally, a larger proportion of water-soluble comonomer is preferred for high molecular weight polymers and a larger proportion of water-insoluble comonomer is preferred for low molecular weight polymers.
In some instances, however, higher molecular weight materials may be useful. For example, a water soluble copolymer of acrylic acid and methacrylic acid may have a weight average molecular weight of 80,000 to 500,000, more preferably 100,000 to 350,000, and most preferably 130,000 to 200,000. In the higher weight average molecular weight copolymers, the acrylic acid preferably comprises 1 to 20 weight percent, more preferably 5 to 15 weight percent, while the methacrylic acid correspondingly provides 99 to 80 weight percent, more preferably, 95 to 85 weight percent, the sum of the acrylic acid and methacrylic acid equaling 100 weight percent.
Included within the class of (xcex1- and/or xcex2-substituted) acrylic acid polymers are acrylic polymers; i.e., polyacrylic acid, copolymers of acrylic acid and one or more other monomers that are copolymerizable with acrylic acid, and blends of polyacrylic acid and one or more acrylic acid copolymers. These can be produced using well-known techniques for polymerizing ethylenically unsaturated monomers. Also included within the class of (xcex1- and/or xcex2-substituted) acrylic acid polymers, and most preferred, are methacrylic polymers; i.e., polymethacrylic acid, copolymers of methacrylic acid and one or more other monomers that are copolymerizable with methacrylic acid, and blends of polymethacrylic acid and one or more methacrylic acid copolymers. The methacrylic polymers useful in the invention can also be prepared using methods well-known in the art for polymerization of ethylenically unsaturated monomers.
Monomers useful for copolymerization with either the acrylic acid or the methacrylic acid have ethylenic unsaturation. Such monomers include monocarboxylic acids, polycarboxylic acids, and anhydrides of the mono- and polycarboxylic acids; substituted and unsubstituted esters and amides of carboxylic acids and anhydrides; nitriles; vinyl monomers; vinylidene monomers; monoolefinic and polyolefinic monomers; and heterocyclic monomers. Specific representative monomers include acrylic acid, itaconic acid, citraconic acid, aconitic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, cinnamic acid, oleic acid, palmitic acid, vinyl sulfonic acid, vinyl phosphonic acid, and substituted or unsubstituted alkyl and cycloalkyl esters of these acids, the alkyl or cycloalkyl groups having 1 to 18 carbon atoms such as methyl, ethyl, butyl, 2-ethylhexyl, octadecyl, 2-sulfoethyl, acetoxyethyl, cyanoethyl, hydroxyethyl, b-carboxyethyl and hydroxypropyl groups. Also included are amides of the foregoing acids, such as acrylamide, methacrylamide, methylolacrylamide, 1,1-dimethylsulfoethylacrylamide, acrylonitrile, and methacrylonitrile. Various substituted and unsubstituted aromatic and aliphatic vinyl monomers may also be used; for example, styrene, a-methylstyrene, p-hydroxystyrene, chlorostyrene, sulfostyrene, vinyl alcohol, N-vinyl pyrrolidone, vinyl acetate, vinyl chloride, vinyl ethers, vinyl sulfides, vinyl toluene, butadiene, isoprene, chloroprene, ethylene, isobutylene, and vinylidene chloride. Also useful are various sulfated natural oils such as sulfated castor oil, sulfated sperm oil, sulfated soybean oil, and sulfonated dehydrated castor oil. Particularly useful monomers include ethyl acrylate, butyl acrylate, itaconic acid, styrene, sodium sulfostyrene, and sulfated castor oil, either alone or in combination. The methacrylic polymers may be polymerized in the presence of chain transfer agents or other polymers which may incorporate into the methacrylic polymer during polymerization.
In the methacrylic polymers, the methacrylic acid preferably provides 20 to 100 weight percent, more preferably 60 to 90 weight percent, of the polymer. The optimum proportion of methacrylic acid in the polymer depends on the comonomer(s) used, the molecular weight of the copolymer, and the pH at which the material is applied. When water-insoluble comonomers such as ethyl acrylate are copolymerized with methacrylic acid, they may comprise up to 40 weight percent of the methacrylic polymer. When water-soluble comonomers such as acrylic acid or sulfoethyl acrylate are copolymerized with methacrylic acid, the water soluble comonomers preferably comprise no more than 30 weight percent of the methacrylic polymer and preferably the methacrylic polymer also comprises up to 50 weight percent water-insoluble monomer.
Commercially available acrylic polymers useful as stainblocking polymers include Acrysol(trademark) (available from Rohm and Haas Company) and Carbopol(trademark) from B. F. Goodrich. Commercially available methacrylic polymers generally useful in the present invention include the Leukotan(trademark) family of materials such as Leukotan(trademark) 970, Leukotan(trademark) 1027, Leukotan(trademark) 1028, and Leukotan(trademark) QR 1083, available from Rohm and Haas Company.
Polymers of (xcex1- and/or xcex2-substituted) acrylic acid monomers useful in the stainblocking compositions of the invention are described in U.S. Pat. No. 4,937,123 (Chang et al.), U.S. Pat. No. 5,074,883 (Wang), and U.S. Pat. No. 5,212,272 (Sargent et al.).
A third class of stainblocking polymers useful in the invention are hydrolyzed polymers of maleic anhydride and at least one or more ethylenically unsaturated monomers. The unsaturated monomer may be an alpha-olefin monomer or an aromatic monomer, although the latter is preferred. A variety of linear and branched chain alpha-olefins may be used including alkyl vinyl ethers. Particularly useful alpha-olefins are 1-alkenes containing 4 to 12 carbon atoms, such as isobutylene, 1-butene, 1-hexene, 1-octene, 1-decene, and 1-dodecene, with isobutylene and 1-octene being preferred, and with 1-octene being most preferred. A portion of the alpha-olefins can be replaced by one or more other monomers, e.g., up to 50 wt. % of alkyl (C1-4) acrylates, alkyl (C1-4) methacrylates, vinyl sulfides, N-vinyl pyrrolidone, acrylonitrile, acrylamide, as well as mixture of the same.
A variety of ethylenically unsaturated aromatic monomers may be used to prepare the hydrolyzed polymers. The ethylenically unsaturated aromatic monomers may be represented by the general formula: 
wherein R is R1xe2x80x94CHxe2x95x90C(R2)xe2x80x94 or CH2xe2x95x90CHxe2x80x94CH2; R1 is Hxe2x80x94, CH3xe2x80x94 or phenyl R2 is Hxe2x80x94 or CH3xe2x80x94; R3 is Hxe2x80x94 or CH3Oxe2x80x94; R4 is Hxe2x80x94, CH3xe2x80x94, or acetyl and R3 plus R4 is xe2x80x94CH2xe2x80x94Oxe2x80x94CH2xe2x80x94Oxe2x80x94CH2xe2x80x94.
Specific examples of ethylenically unsaturated aromatic monomers include free radically polymerizable materials such as styrene, xcex1-methylstyrene, 4-methyl styrene, stilbene, 4-acetoxystilbene (used to prepare a hydrolyzed polymer from maleic anhydride and 4-hydroxy-stilbene), eugenol, isoeugenol, 4-allylphenol, safrole, mixtures of these materials, and the like. Styrene is most preferred. The utility of some of these materials may be improved by increasing the amount of polymerization initiator or acylating or etherifying the phenolic hydroxy groups.
In the hydrolyzed polymers, the ratio of units derived from ethylenically unsaturated monomer to units derived from maleic anhydride is 0.4:1 to 1.3:1 when the unsaturated monomer is an alpha-olefin, and is 1:1 to 2:1 when using an unsaturated aromatic monomer. In any event, a ratio of 1:1 is most preferred.
Hydrolyzed polymers suitable for use in the invention may be prepared by hydrolyzing ethylenically unsaturated maleic anhydride polymers. Alkali metal hydroxides (such as potassium hydroxide, lithium hydroxide and, most often, sodium hydroxide, as well as blends of these) are suitable hydrolyzing agents. Hydrolysis can be effected in the presence of more than or less than a molar amount of the alkali metal hydroxide. The presence of an alcohol in the hydrolysis mixture should be avoided.
Hydrolyzed polymers of at least one or more alpha-olefin monomers and maleic anhydride useful in the stainblocking compositions of the invention are described in U.S. Pat. No. 5,460,887 (Pechhold). Hydrolyzed polymers of at least one or more ethylenically unsaturated aromatic monomers and maleic anhydride useful in the stainblocking compositions of the invention are described in U.S. Pat. No. 5,001,004 (Fitzgerald et al.).
Useful stainblocking polymers may be obtained: (1) by blending together at least two or more polymers selected from among the different general classes of polymers described above; (2) by reacting together at least two or more monomers from which the different general classes of polymers are derived; (3) as the reaction product of at least one or more of the monomers from which the polymers may be derived and at least one or more of the polymers; or (4) by polymerizing at least one or more of the monomers in the presence of one or more of the polymers.
For example, one or more (xcex1- and/or xcex2-substituted) acrylic acid monomers may be polymerized together and, subsequent to the polymerization, blended with a sulfonated aromatic polymer. This permits both the carboxyl functionality from the (xcex1-and/or xcex2-substituted) acrylic acid polymer and the sulfonate functionality from the sulfonated aromatic polymer to contribute to the stainblocking properties of the composition. Particularly useful examples of such blends comprise a sulfonated aromatic condensation polymer (e.g., the condensation polymerization product of an aldehyde such as formaldehyde or acetaldehyde, a hydroxyaromatic compound such as bis(hydroxyphenyl)sulfone, phenol or napthol, and phenylsulfonic acid), and methacrylic polymer (e.g., polymethacrylic acid or a copolymer of methacrylic acid and or more of the following monomers: ethyl acrylate, butyl acrylate, itaconic acid, styrene, sodium sulfostyrene, sulfated castor oil, and acrylic acid).
The amounts of the sulfonated aromatic polymer and the (xcex1- and/or xcex2-substituted) acrylic acid polymer used should be sufficient to provide the desired degree of stain resistance to the substrate. Generally, when the substrate is nylon 6,6, lower application levels can be used than when the substrate is nylon 6 or wool. When the substrate is yarn heat-set under moist conditions (e.g., in an autoclave), generally higher application levels are required than when the yarn is heat-set under substantially dry conditions. Preferably, the amount of sulfonated aromatic polymer is at least 0.1% SOF, more preferably at least 0.2% SOF, most preferably at least 0.4% SOF when treating nylon 6,6 carpet fiber. Generally, amounts of sulfonated aromatic polymer in excess of 2% SOF provide little added benefit. Preferably the amount of (xcex1- and/or xcex2-substituted) acrylic acid polymer is at least 0.1% SOF, more preferably at least 0.2% SOF, most preferably at least 0.4% SOF when treating nylon 6,6 carpet fiber. Generally amounts of (xcex1- and/or xcex2-substituted) acrylic acid polymer in excess of 2% SOF provide little added benefit. Preferably, the amount of sulfonated aromatic polymer used is at least 0.2% SOF, more preferably at least 0.4% SOF, based on the weight of the fiber when treating nylon 6 carpet fiber. Preferably, the amount of (xcex1- and/or xcex2-substituted) acrylic acid polymer is at least 0.2 more, % SOF, preferably at least 0.4% SOF when treating nylon 6 carpet fiber.
Alternatively, the (xcex1-and/or xcex2-substituted) acrylic acid monomer may be polymerized in the presence of the sulfonated aromatic polymer. Examples of such compositions comprise an axe2x80x94substituted acrylic acid monomer (e.g., having the structure H2Cxe2x95x90C(R)CO2H, wherein R is an alkyl group having 1 to 4 carbon atoms, phenyl, phenol, sulfonated phenol, naphthol, chlorine or fluorine) polymerized in the presence of a sulfonated aromatic condensation polymer (e.g., the condensation polymerization product of an aldehyde such as formaldehyde or acetaldehyde, a hydroxy aromatic compound such as bis(hydroxyphenyl)sulfone, phenol or napthol, and phenylsulfonic acid). Such techniques are described in U.S. Pat. No. 4,940,757 (Moss, III et al.).
A free radical polymerization initiator is added to initiate polymerization of the (xcex1- and/or xcex2-substituted) acrylic acid monomer in the presence of the sulfonated aromatic polymer. Useful initiators include persulfates (e.g., potassium persulfate, ammonium persulfate, or sodium persulfate), peroxides (e.g., sodium peroxide, hydrogen peroxide, benzoyl peroxide, acetyl peroxide, lauryl peroxide, cumyl peroxide, t-butyl peroxide, or t-butyl hydroperoxide), azo compounds (e.g., azo-bis-isobutryonitrile), and hydrochloride salts of azo compounds.
In another embodiment, a stainblocking polymer may be prepared by reacting a sulfonated hydroxy aromatic compound with isocyanate, carboxylic acid, carboxylic acid anhydride, carboxylic acid chloride, or other carboxylic acid precursor, any of which may be saturated or unsaturated. The ester formed by this reaction may then be reacted by itself or with an (xcex1- and/or xcex2-substituted) acrylic acid, and a free radical polymerization initiator, either in the presence of or in the absence of another sulfonated aromatic polymer. Alternatively, the ester formed from the first reaction may be homopolymerized or copolymerized with an aromatic compound in an aldehyde condensation reaction. The resulting product can be further reacted, either by itself or with an (xcex1- and/or xcex2-substituted) acrylic acid in the presence of a free radical polymerization initiator. Useful free-radical polymerization initiators include persulfates (e.g., ammonium persulfate, sodium persulfate, or potassium persulfate), peroxides (e.g., sodium peroxide, hydrogen peroxide, benzoyl peroxide, acetyl peroxide, lauryl peroxide, cumyl peroxide, t-butyl peroxide, or t-butyl hydroperoxide), an azo compound (e.g., azo-bis-isobutyronitrile), and peracetate (e.g., t-butyl peracetate). Such techniques are described in U.S. Pat. No. 5,310,828 (Williams et al.).
Other useful combinations include hydrolyzed polymers of ethylenically unsaturated monomer and maleic anhydride blended with sulfonated aromatic polymers and/or polymers of (xcex1- and/or xcex2-substituted) acrylic acid. For example, a part of the maleic anhydride (up to 30 weight %) can be, replaced by acrylic or methacrylic acid. In another embodiment, a part (preferably 1-75% by weight) of the maleic anhydride can be replaced by maleimide, N-alkyl (C1-4) maleimides, N-phenyl-maleimide, fumaric acid, itaconic acid, citraconic acid, aconitic acid, crotonic acid, cinnamic acid, alkyl (C1-18) esters of the foregoing acids, cycloalkyl (C2-8) esters of the foregoing acids, sulfated castor oil, or the like.
Particularly preferred blends comprise 95 to 30 weight % of hydrolyzed polymer of ethylenically unsaturated aromatic monomer and maleic anhydride (more preferably, 85 to 40 weight %), and 5 to 70 weight % of a sulfonated aromatic condensation polymer, e.g., a sulfonated phenol-formaldehyde condensation polymer (more preferably, 15 to 60 weight %), wherein the sum of these two components is 100 weight %. Such combinations are described in U.S. Pat. No. 4,833,839 (Fitzgerald et al.).
Suitable silsesquioxane polymers for use in this invention are those described in U.S. patent application Ser. No. 09/607,667 now abandoned, which is incorporated herein by reference.
The silsesquioxane materials can be any of the types described in U.S. Pat. Nos. 4,781,844 (Kortmann, et al), 4,351,736 (Steinberger et al.), 5,073, 442 (Knowlton et al.) or 3,493,424 (Mohrlok et al.) each of which are incorporated herein by reference. These silsesquioxane polymers are of the formula Rxe2x80x94SiO3/2 or Rxe2x80x94Si(ORxe2x80x2)3 alone or together with silanes of the formula Si(ORxe2x80x2)4 and/or R2xe2x80x94Si(ORxe2x80x2)2 wherein R represents a substituted or unsubstituted hydrocarbon radical having 1 to 7 carbon atoms, substituents of which may be halogen atoms and mercapto and epoxy groups. Rxe2x80x2 represents an alkyl radical with 1 to 4 carbon atoms. Preferred silsesquioxane polymers are those that are neutral or anionic.
The silsesquioxane polymers may be prepared by adding silanes to a mixture of water, a buffer, a surface active agent and optionally an organic solvent, while agitating the mixture under acidic or basic conditions. It is preferable to add the quantity of silane uniformly and slowly in order to achieve a narrow particle size of 200 to 500 Angstroms. The exact amount of silane that can be added depends on the substituent R and whether an anionic or cationic surface active agent is used.
Silsesquioxane copolymers in which the units can be present in block or random distribution are formed by the simultaneous hydrolysis of the silanes. The preferred amount of silane of the formula Si(ORxe2x80x2)4 added is 2 to 50 percent, relative to the total weight of the silanes employed, preferably 3 to 20 percent.
The following silanes are useful in preparing the silsesquioxane polymers of the present invention: methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxyoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, 2-ethylbutyltriethoxysilane, tetraethoxysilane, and 2-ethylbutoxytriethoxysilane.
The surfactants, or surface active agents, useful as foaming agents in the cleaning/treating solutions of this invention are synthetic or natural organic compounds or materials capable of foaming water. Those surfactants which are preferred are those sometimes characterized as capable of forming xe2x80x9cstrongly foaming solutionsxe2x80x9d, e.g., see xe2x80x9cFoamsxe2x80x9d, J. J. Bikerman, published by Springer-Verlag, New York, Inc., pages 108-132 (1973). The usefulness of a surfactant, and its amount, for purposes of this invention, can be determined by the foam volume or height and its resistance to collapse. Generally, the applicable surfactant(s) and amount thereof useful in producing the foams of this invention will yield a foam volume (or height) at least one-and-a-half, and preferable at least twice, that of the foamable aqueous solution, a simple test for this purpose being the shaking by hand of the test solution in a suitable closed container. For example, 100 g of such solution is vigorously shaken 25 times in a 480 mL, or larger, closed glass jar or a calibrated vessel, and the height of the resulting foam vis-a-vis the height of the solution before shaking is measured, the ratio of foam height to solution height being the expansion value.
The hydrocarbon surfactants useful in this invention can be anionic, nonionic, cationic, or amphoteric, and compatible mixtures thereof. Classes of surfactants which are useful include: soaps or the salts of fatty acids, such as those having the general formula RCOOM, where R is a fatty aliphatic group and M is an alkali metal, e.g., sodium oleate, laurate, palmitate, or stearate; fatty alkyl sulfates, such as those of the general formula ROSO2OM, e.g., sodium decyl, dodecyl, tetradecyl, hexadecyl, heptadecyl, or octadecyl sulfate; RSO3M, e.g., sodium decyl, dodecyl, tetradecyl, hexadecyl, heptadecyl, or octadecyl sulfonate; salts of alkarylsulfonic acids, such as those of the general formula RC6H4SO3M, e.g., sodium octylbenzene sulfonate or sodium xylene sulfonate; ethylene oxide adducts, such as those of the general formula R(CH2CH2O)nH where R is a fatty aliphatic radical, e.g., where R is C10H21O to C18H37O and n is 10 to 60; those of the general formula R(OCH2CH2)nOSO3M, where R is a C10 to C1-8 alkyl group, n is 1 to 3, and M is sodium; and salts of dialkyl sulfosuccinic acids, e.g., sodium dioctyl sulfosuccinate. Also see Encyclopedia of Chemical Technology, Kirk-Othmer, 3rd Ed., Vol. 22, pages 347-387, John Wiley and Sons (1983) for other surfactants useful in this invention.
Useful surfactants include anionic surfactants alone or in combination with other surfactants such as, for example, nonionic surfactants. Any anionic surfactant can be used in the composition, so long as the anionic surfactant is compatible with the other elements of the composition, and provides detergency desired to clean a soiled carpet. Suitable anionic surfactant or surfactants can contain one or two hydrophobic groups and one or two water-solubilizing anionic groups.
The hydrophobic group(s) should be large enough to make the surfactant sufficiently surface active, i.e., the total number of carbon atoms in all hydrophobic groups can preferably be at least 8. Examples of suitable hydrophobic groups include straight and branched octyl, decyl, lauryl (i.e., mostly dodecyl), myristyl (i.e., mostly tetradecyl), cetyl (i.e., mostly hexadecyl) and stearyl (i.e., mostly octadecyl); dodecylbenzyl, naphthyl, xylyl and diphenyl. Heteroatom-containing moieties may be present in the hydrophobic group, e.g., ester, amide and ether. When more than one hydrophobic group is present, the length of the chain may be relatively shorter (e.g., two n-butyl groups).
The water-solubilizing anionic group can preferably be sufficiently polar to effectively solubilize the surfactant in water to allow formation of micelles. Suitable water-solubilizing anionic groups include sulfonate, sulfate, and carboxylate. The positive counterion for the anionic group can be an alkali metal ion (e.g., Na+, K+ or Li+), an alkaline earth metal ion (e.g., Mg++ or Ca++), or an ammonium ion (e.g., NH4+ or triethanolammonium). Optionally, the water-solubilizing anionic group can also contain a polyoxyethylene group of 1-15 monomeric units located between the hydrophobic group and the charged ionic group to form an ether sulfate, ether sulfonate or ether carboxylate group.
The total amount of surfactant present in a concentrate composition generally is in an amount in the range from 0.1% to 10% by weight, preferably from 0.5% to 6%, by weight and more preferably from 1% to 3% by weight. When used in the form of an aqueous use dilution, the surfactant can generally be present in an amount of 0.002% to 0.156% by weight, preferably 0.008% to 0.094% by weight, and more preferably 0.016% to 0.047% by weight.
Examples of suitable anionic surfactants include sodium xylene sulfonate, sodium lauryl sulfate, sodium myristyl sulfate, sodium lauryl ether (2) sulfate (i.e., C12H25(OCH2CH2)2OSO3xe2x88x92Na+), sodium decyl sulfate, ammonium myristyl ether sulfate, sodium nonylphenol polyglycol ether (15) sulfate, sodium C16-C18 xcex1-olefin sulfonate, sodium dodecylbenzenesulfonate, sodium naphthyl sulfonate, sodium dihexyl sulfosuccinate, sodium laurate, sodium stearate, sodium ether (5) stearate, potassium ricinoleate (potassium 12-hydroxy-9-octadecanoate), sodium myristoyl sarcosine and sodium N-methyl-N-oleyl taurate. The preferred surfactant is sodium xylene sulfonate. Such anionic surfactants are commercially available from many suppliers, many of whom are listed in the McCutcheon""s Emulsifiers and Detergents directory, North America or International Editions (1996).
The anionic surfactant can generally be present in a concentrate composition in an amount in the range from 0.25% to 10% by weight, preferably from 0.5% to 6%, by weight and more preferably from 0.75% to 1% by weight. When used in the form of an aqueous use dilution, the surfactant can generally be present in an amount of 0.004% to 0.156% by weight, preferably 0.008% to 0.094% by weight, and more preferably 0.012% to 0.016% by weight.
The nonionic surfactants of the present invention include those having a hydrophobic/lipophilic balance (HLB) value (also called HLB number) of at least 18. HLB values measure the polarity of a nonionic surfactant, with least hydrophilic/most lipophilic surfactants (i.e., those having a low level of ethoxylation) having a low HLB value and most hydrophilic/least lipophilic surfactants (i.e., those having a high level of ethoxylation) having a high HLB value. For a more detailed description of HLB values, see Nonionic Surfactants: Physical Chemistry, vol. 23, ed. M. J. Schick, pp.438-456 (1987). Examples of suitable nonionic surfactants include nonylphenol polyethylene glycol ether Tergitol(trademark) 15-S-40 (Dow Chemical, Midland, Mich.), which has an HLB value of 18.
The nonionic surfactant can generally be present in a concentrate composition in an amount in the range from 0.25% to 10% by weight, preferably from 0.5% to 6%, by weight and more preferably from 1% to 2% by weight. When used in the form of an aqueous use dilution, the surfactant can generally be present in an amount of 0.004% to 0.156% by weight, preferably 0.008% to 0.094% by weight, and more preferably 0.016% to 0.031% by weight.
The composition may optionally contain a sequestering agent to chelate hardness ions such as calcium, magnesium, iron, manganese and the like that might be present in an aqueous use dilution water and detract from the cleaning performance of the composition. The sequestering agent can be organic or inorganic. Organic sequestering agents include a broad range of materials that can complex hardness ions. These include EDTA and its salts, citric acid and its salts, boric acid and its salts, nitrilotriacetic acid and its salts, polyelectrolytes such as polyacrylic acid and its copolymers, polymaleic acid and its copolymers, and so on. Inorganic sequestering agents include condensed phosphates, particularly those of the formula Mxe2x80x94(PO3M)nOM wherein M is an alkali metal, n is a number ranging from 1 to 60, typically less than 3 for non-cyclic phosphates. Examples of such phosphates include alkali metal orthophosphates such as sodium or potassium orthophosphate and alkali metal condensed phosphates (i.e., polyphosphates) such as sodium or potassium pyrophosphate, sodium tripolyphosphate, sodium hexametaphosphate and the like. A preferred sequestering agent is sodium tripolyphosphate, due to its sequestration and soil suspension properties. The sequestering agent can generally be present in an amount in the range from 2% to 12% by weight of a concentrate composition, preferably from 3% to 9% by weight and more preferably from 5% to 7% by weight. The sequestering agent can typically be present in an aqueous use dilution in an amount in the range from 0.047% to 0.188% by weight, preferably from 0.031% to 0.141% by weight, and more preferably from 0.078% to 0.109% by weight.
The composition may optionally contain salts for improving the deposition of the stainblocking polymer onto the carpet. Useful salts include metal salts and ammonium salts. Suitable salts for use in the present invention include divalent metal salts such as MgSO4, MgCl2, CaCl2, Ca(CH3COO)2, SrCl2, BaCl2, ZnCl2, ZnSO4, FeSO4 and CUSO4; monovalent metal salts such as LiCl, NaCl, NaBr, NaI, KCl, CsCl, Li2SO4 and Na2SO4; polyvalent metal salts such as AlCl3 and aluminum citrate; and ammonium salts such as NH4Cl, (NH4)2SO4, and (CH3)4NCl. Divalent metal salts are generally preferred, with magnesium salts (e.g., MgSO4) being especially preferred, although good results can also be obtained under certain conditions through the use of monovalent metal salts or polyvalent metal salts or ammonium salts. The salt is most effective when applied at levels of 0.1 to 3%, preferably 0.5 to 3%, solids on carpet in the cleaning and treating composition.
The composition may optionally contain base and/or buffer to adjust the pH of the composition to its optimal working range. While the optimal pH for the treatment compositions may vary depending on the choice of materials, optimal results are generally obtained when the composition has an initial pH, or adjusted pH, of at least 6. Preferably, the composition has an initial pH, or adjusted pH, in the range of 6 to 8. If the pH of the cleaning/treating composition is kept below 6, the composition does not remain homogeneous due to precipitation of the silsesquioxane polymer. When the pH of the composition is above 8, the stainblocking performance continually diminishes with increasing pH.
Typically when formulating the compositions of this invention, an upward pH adjustment to near neutrality is required due to the high inherent acidity of most stainblocking polymers. To make this upward pH adjustment, small amounts of strong bases such as sodium or ammonium hydroxide can be used. However, to better control the pH of the composition over an extended period of time, incorporation of larger amounts of a buffer can be employed. Many inorganic and organic salts are useful as buffers for stabilizing the pH of the composition in the range of 6-8, including: mixtures of disodium hydrogen phosphate and potassium dihydrogen phosphate, sodium bicarbonate, disodium tetraborate, mixtures of tris(hydroxymethylaminomethane) (TRIS) and TRIS hydrochloride, ammonium acetate, and histidyl-glycine. Buffers can be used at a molar concentration range of 0.001 molar (M) to 1 M in the concentrate form of the composition, or from 0.000015 M to 0.015 M in the aqueous use dilution form of the composition. (For further information on buffers, see CRC Handbook of Chemistry and Physics, 2000-2001, 81st Ed., Ed. D. R. Lide, pp. 8-35 to 8-40.)
The composition may optionally contain other ingredients, such as anti-foaming agents, fragrances, preservatives, and the like. If used, these added ingredients are typically present in relatively small amounts, such as 0.05% to 0.20% by weight of the composition in concentrate form, or from 0.0008% to 0.0031% by weight of the aqueous use dilution.
Although it is preferred and possible that the composition contain no organic solvent, it may be necessary that a very small amount of a compatible organic solvent be contained in the composition, e.g., because it has been included as part of the commercially available ingredients used (e.g., as a solvent or remnant of production), or, in order to dissolve one or more other ingredients within the composition. Generally, this amount will preferably be below 1% by weight, more preferably less than 0.5% by weight, and more preferably less than 0.1% by weight of the concentrate composition, so that in effect the composition essentially contains no organic solvent.
The composition may be prepared as a concentrate that contains a concentrated solution of the components described above, or as an xe2x80x9caqueous use dilutionxe2x80x9d wherein the above concentrate is combined with a sufficient amount of water to provide a solution that can be used with standard carpet cleaning equipment. In general, the aqueous use dilution can be prepared by diluting 1 to 2 parts by weight of the concentrate with from 99 to 98 parts by weight water.
The compositions of the invention can be prepared by combining the ingredients, heated or unheated, with stirring until a uniform mixture is obtained.
This invention can be employed to clean carpets constructed from a variety of fibers, including polyamide (e.g., nylon 6 and nylon 6,6), wool, polyolefin (e.g., polypropylene), polyester, acrylic, and blends thereof. Preferably, the fiber is a polyamide or a polyamide blend fiber.
In the method of the invention, a cleaning and treating composition of this invention can be applied to a carpet using cleaning methods known in the carpet cleaning art. A preferred method includes a water extraction step, wherein the temperature of the cleaning and treating composition during hot water extraction, e.g., the composition after aqueous use dilution, is preferably at least 50xc2x0 C., and wherein the composition can be delivered to a carpet by employing a high pressure pump system. Following the water extraction step, the spent composition, i.e., the soiled aqueous use composition resulting after exposure to the carpet, can be subsequently removed from the carpet by employing a first vacuum removal step with a wet vacuum system. The 1st vacuum removal step can occur within 60 minutes, preferably within 10 minutes, more preferably within 1 minute, and most preferably within 10 seconds from the onset of the water extraction step. It is desirable to minimize this exposure time to facilitate the removal of the cleaning and treating composition from the contacted carpet fibers. One or more additional steps of hot water extraction followed by vacuum removal can be employed to further clean and treat the carpet. Removal of cleaning and treating composition residuals can be optimized by employing a water rinsing step followed by a second vacuum removal step, both performed within 60 minutes, preferably within 10 minutes, more preferably within 1 minute, and most preferably within 10 seconds after the completion of the first vacuum removal step. Optimum cleaning and treating of the carpet can result by employing this sequence of a water extraction step, a first vacuum removal step, a water rinsing step and a second vacuum removal step, though this invention can be also practiced by employing only the water extraction step and first vacuum removal step. After the water extraction step, vacuum removal step, water rinsing step, and second vacuum removal step, or a series or combination thereof, the carpet is allowed to dry. After the soiled carpet is cleaned with a cleaning and treating composition of this invention, the resulting cleaned carpet continues to exhibit at least a portion of, and usually a large extent of, the original stainblocking and soil resistance properties imparted by the original carpet treatment applied at the time of manufacture.
The stainblocking and soil resistance properties of the substrate can be further enhanced by the use of an additional step where an aqueous composition including a stainblocker and a silsesquioxane, as defined above, is applied to the cleaned and treated substrate. Preferably, this additional step is performed on the cleaned and treated substrate prior to drying.
The invention is further described by reference to the following examples, which are understood to be illustrative and non-limiting of the invention. Unless otherwise specified, all percentages shown in the examples and test methods which follow are percentages by weight.
One exemplary composition comprises: a) 1 to 4 weight percent of a stainblocker; b) 1 to 4 weight percent silsesquioxane; and c) 1 to 4 weight percent surfactant. A second exemplary composition comprises: a) 2 to 3 weight percent of a stainblocker; b) 2 to 3 weight percent silsequioxane; and c) 2 to 3 weight percent surfactant.